Ultra-high modulation depth exceeding 2,400% in the optically-controlled topological surface plasmons
SCIE
SCOPUS
- Title
- Ultra-high modulation depth exceeding 2,400% in the optically-controlled topological surface plasmons
- Authors
- Sim, S; Jang, H; Koirala, N; Brahlek, M; Moon, J; Sung, J.H; Park, J; Cha, S; Oh, S; Jo, M.-H; Ahn, J.-H; Choi, H.
- Date Issued
- 2015-10
- Publisher
- Nature Publishing Group
- Abstract
- Modulating light via coherent charge oscillations in solids is the subject of intense research topics in opto-plasmonics. Although a variety of methods are proposed to increase such modulation efficiency, one central challenge is to achieve a high modulation depth ( defined by a ratio of extinction with/without light) under small photon-flux injection, which becomes a fundamental trade-off issue both in metals and semiconductors. Here, by fabricating simple micro-ribbon arrays of topological insulator Bi2Se3, we report an unprecedentedly large modulation depth of 2,400% at 1.5 THz with very low optical fluence of 45 mu J cm(-2). This was possible, first because the extinction spectrum is nearly zero due to the Fano-like plasmon-phonon-destructive interference, thereby contributing an extremely small denominator to the extinction ratio. Second, the numerator of the extinction ratio is markedly increased due to the photoinduced formation of massive two-dimensional electron gas below the topological surface states, which is another contributor to the ultra-high modulation depth.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/35817
- DOI
- 10.1038/NCOMMS9814
- ISSN
- 2041-1723
- Article Type
- Article
- Citation
- Nature Communications, vol. 6, 2015-10
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